FIDH has documented widespread sexual harassment, rape and sexual assault, rape with objects, anal and vaginal "virginity tests", electrocution of genitalia, sex-based defamation and blackmail perpetrated by police, state security and military personnel.

The report said the "multiplication of arbitrary arrests has targeted an increasingly diverse range of victims: women, refugees, minors, students, opponents to the regime or otherwise, and LGBT persons are now frequent victims".

The report reveals the involvement of police, intelligence officers and the military in sexual violence [EPA]

Katherine Booth, of the FIDH in Paris, told Al Jazeera that her organisation decided to conduct an investigation after receiving increasing reports of sexual abuse by Egyptian authorities.

"We do know that such crimes are being committed in police stations, detention centres and informal detention sites as well as at checkpoints during security checks," Booth said.

"There's a very widespread nature to the crimes and nobody has been held to account which could indicate that this is tolerated by the Egyptian authorities, if not encouraged."

Interviews with victims

FIDH conducted interviews with victims, lawyers and members of human-rights nongovernmental organisations (NGO).

According to one NGO quoted in the report, at least 16 complaints had been lodged by parents of detained children, alleging that their sons had been victims of physical assault.

Another NGO had been informed of 10 sexual assaults, including several rapes of minors by adult prisoners at the El Eqabiya detention centre in Al Marg, northeast of Cairo.

In August 2014, three testimonies broadcast by the journalist Mona Salman on the private channel Dream TV reported widespread rape committed in the Eqabiya detention centre, where around 90 minors are detained alongside adult criminals, under the supervision of Criminal Intelligence services.

Groups supporting the Muslim Brotherhood reported that of 1,500 women members of the group in prison, at least 20 cases of rape and several cases of forced abortion had been documented.

There were also reported cases of prisoners forced to watch pornographic videos and to wash floors with their naked bodies.

Between 2011 and 2014, FIDH also documented sexual violence committed against women in public, from cases of mob rape and sexual assault perpetrated by civilians during demonstrations around Tahrir Square.

"The scale of sexual violence occurring during arrests and in detention, the similarities in the methods used and the general impunity enjoyed by the perpetrators point to a cynical political strategy aimed at stifling civil society and silencing all opposition," said Karim Lahidji, FIDH president.

'Dragged along the floor'

A student who was a detainee was quoted in the FIDH report as saying: "The women guards came at dawn to drag us along the floor without giving us time to cover ourselves appropriately.

"They lined us up facing the wall and we were surrounded by members of the anti-riot force and the guards then started frisking us while undressing us and harassing us."

The Egyptian constitution, adopted in January 2014, guarantees equal rights for men and women and obliges the state to take the necessary measures to protect women from all forms of violence.

Since then, several "inadequate" steps have been taken to increase protection, the FIDH said, but since the takeover by the army in July 2013, sexual violence has appeared "as a central element of the unprecedented repression to which opponents and civil society are subjected".

The report said that the fact that those in power were using sexual violence was itself a tool that scared victims from speaking out.